Explosive



Patented Aug. 29, 1933 PATENT OFFICE EXPLOSIVE Hubert H. Champney,

Succasunna, N. .L, as-

signor to Hercules Powder Company, Wilmington, DeL, a corporation of Delaware No. Drawing.

7 Claims.

My invention relates to an improvement in explosives and more particularly what are generally known as permissible explosives, such as are used for commercial purposes, as in connection with the mining of coal.

It has been heretofore generally recognized that, for many purposes, explosives of the character of black powder are greatly superior to those explosives which detonate, since the rending action of black powder is in many instances more desirable than the shattering eflfects of explosives which detonate. Such is especially true in connection with the mining of coal and more particularly in connection with the mining of soft coal, where the use of an explosive which 'detonates results, due to the shattering effect, in the production of an undesirably large quantity of small sizes and slack coal as compared with the production of lumps, with a minimum of small sizes and slack where black powder is used.

Heretofore continuous efforts have been made Witha view to enable the effect of black powder to be obtained with detonating explosives. Such efiorts have produced various solutions for the problem, but with few exceptions-"Fhave not proved highly practical. The only really successful solution for the problem is provided by the explosive forming the subject matter of the United States Patent No. 1,671,193 dated May 29, 1928, to Buren I. Stoops, which involves an explosive of the permissible type, i. e., including ammonium nitrate and an oxidizing salt and of such a density or bulk relative to its shattering power as in use to enable the power to be so distributed as to negative the shattering efiect and give essentially the same result in, for ex-.

ample, coal, as that obtained with the use of black powder. The merit of the explosive covered by the Stoops Patent No. 1,671,793 depends upon the use of a substantially large quantity of low density carbonaceous material, the tendency of which to absorb the sensitizer included in the explosive being negatived by the impregnation of 4 salt ingredients of the explosive into the carbonaceous material, the absorptive capacity of which is thus substantially satisfied.

According to the Stoops patent, an explosivemay be produced of such density as to permit the production of a cartridge count of in excess of 425 standard 1%X8" cartridges per 100 pounds of explosive, and cartridge counts of substantially over 500 may be obtained, with the result that the explosive, involving essentially the inmonium and sodium nitrate, a sensitizer, and

Application October 5, Serial No. 397,752

gredients of a permissible explosive, that is, am-- carbonaceous material, may be made to produce substantially the same effect as is produced by black powder.

Now it is the object of my invention to provide an explosive, more particularly of the permissible type, that is, including ammonium nitrate, or an equivalent, an oxidizing salt, a sensitizer, and a carbonaceous material, which will produce substantially the same effect as that produced by black powder, without the necessity for impregnating the carbonaceous material, or, in other words, with the several ingredients in mechanical mixture, as is customary in explosives of the permissible type.

In accordance with my invention, I provide an explosive the essential ingredient of which comprises crystallized ammonium nitrate having a density within about the range 0.50-0.80 gm. per cc., and with which is mechanically admixed an oxidizing salt, as sodium or potassium nitrate, or the like, carbonaceous material, as wood flour, bagasse, bagasse pith, or any'other suitable carbonaceous material, and a sensitizer, as a liquid high explosive, such as nitroglycerin, nitroglycol, or the like.

In preparing the explosive in accordance with my invention, it is only necessary to admix crystalline ammonium nitrate having a density within the range about 0.50-.-0.80 gm. per cc. with the several other ingredients, the crystalline ammonium nitrate being in major proportion and desirably in dominating proportion. The explosive produced by the mechanical admixture of the several ingredients is cartridged in any well known manner and is then ready for use. The density of the explosive will be such that a cartridge count of in excess of 425 standard I AXB cartridges per 100 pounds may be readily obtained, and where the density of the crystalline ammonium nitrate is about 0.50 gm, per 00., a cartridge count of in excess of 500 may readily be obtained.

The density referred to as within the range about 0.50-0.80 gm. per cc. is apparent or gravimetric density. The density value 'in gm. per cc. of the crystalline ammonium nitrate contemplated for use in accordance with this invention may be readily determined with the use of apparatus commonly used by explosive manufacturers for determining apparent or gravimetric density and which comprises primarily a cylinder one square inch in cross section in which the sample is placed and a piston having a dead weight of ten pounds. For determining the apno parent or gravimetric density of crystalline ammeasured and the density of the sample calculated by dividing the weight of the sample in grams by the volume of the sample in cubic centimeters, taken with the sample under the lowered piston.

The crystalline ammonium nitrate having a density within about the range 0.50-0.80 gm. per cc. may be readily prepared by the crystallization of ordinary commercial ammonium nitrate from an aqueous solution thereof. For example, the crystalline ammonium nitrate having a density within the range specified may be produced from -an 80% solution of ordinary commercial ammonium nitrate formed by dissolving sumcient commercial ammonium nitrate in heated water, crystallization being effected at a rapid rate by re-' duction of the temperature of the solution while agitating the solution to a certain extent. The crystalline ammonium nitrate, when formed, is separated from the mother liquor and rapidly dried under conditions of increasing temperature and with minimum agitation.

As a more specific example of the production of the crystallized ammonium nitrate having a density within the range specified, an 80% solution of commercial ammonium nitrate in water at a temperature, say, within about the range 140 F.- 210 F., is cooled down to a temperature of from about F. at a rate of about 2 F. per minute, with minimum agitation. After separation from the mother liquor of the crystals formed, for example, by centrifuging, the crystalline material is dried in a current of warm air, the temperature being gradually raised from, say, about 90 F. at the start to 150 F. at the finish. The drying will be effected in about twenty minutes, during which period any violent agitation of the crystalline material is to be avoided, though certain minimum agitation thereof is desirable.

The following formulae will be illustrative of explosive compositions adaptable for commercial use and having certridge counts in excess of 425 1 X 8" cartridges per 100 pounds:

Nitroglymrinn 12 10 12 Ammonium nitrate 55 Sodium nitrate 8 6 18 P pit 15 10 -15 Cartridges per 100# for ammonium nitrate, dens1ty of 0.50 520 470 480 Cartridges per 100# for ammonium nitrate, denslty of 0.80. 470 440 Sensitivenessfresh 14' 14 16" Sensitiveness-Zi hr. 100 F l4" 14 14 Sensitiveness-l20 hr. 100 F 14 12 14" From the above formula, it will be observed that where crystalline ammonium'nitrate having a density of 0.50 gm. per cc. is used in the amount of 70%, in a composition including bagasse pith,

a lowi density carbonaceous material, in the of 75% and the bagasse pith is reduced to 10%, a

cartridge count of 470 will be obtained, and Where the amount of ammonium nitrate is reduced to 55% where 15% of bagasse pith is used, a cartridge count of 480 is obtained. It will be noted, in accordance with my invention, that an explosive capable of producing a very high cartridge count, and hence having substantially the same effect as black powder,'may be produced easily and at no essentially greater expense than that incident to the production of generally known explosives of similar type.

It will be understood that the essential feature of my invention resides in the use of crystallized amamonium nitrate having a density within the range specified, i. e., (1.50-0.80 gm. per 00., which in the production of commercial explosive may be admixed with any suitable salt, and any suitable sensitizer, and any suitable carbonaceous material; which will desirably be .of low density and may be used in quantity in excess of that heretofore used in explosives without loss of sensitivity due to the fact that the ammonium nitrate having a density within the range 0.50-0.80 gm. per cc. is more sensitive, as well as of lower density, than ammonium nitrate heretofore used in ex- .plosives, because of the natural, truly crystalline state in which it is used in accordance with my invention.

Y What I claim and desire to protect by Letters Patent is:

1. An explosive composition having a density such as to enable the production of in excess of four hundred and twenty-five 1%" x 8" cartridges per 100 pounds including as an ingredient truly crystalline ammonium nitrate in a free state and 2. An explosive composition having a density such as to enable the production of in excess of four hundred and twenty-five 1%." x8" cartridges per 100.pounds including as an ingredient truly crystalline ammonium nitrate in a free cross-section under a dead weight of 10 pounds withinabout the range 0.50-0.80 gm, per cc.

3. An explosive composition having a density such as to enable the production of in excess of four hundred and twenty-five 1 A" 8" cartridges per 100 pounds including as ingredients carbonaceous material and in mechanical admixture therewith crystallized ammonium nitrate having a density, determined by dividing the .weight ingrams of a sample of ammonium nitrate having a volume normally. ofone cubic inch by the volume of said sample in a closed cylinder one square inch in cross-section under a dead weight of 10 pounds within about the \range 0.50-0.80 gm. per cc.

4. An explosive composition having a density I such as to enable the production of in excess of four hundred and twenty-five 1%."x8" cartridges per 100 pounds including as ingredients carbonaceous material, an oxidizing salt, and in mechanical admixture therewith crystallized ammonium nitrate having a gravimetric density, determined by dividing the weight in grams of a sample of ammonium nitrate having a volume normally of one cubic inch by the volume of said sample in a closed cylinder one square inch in cross-section under a dead weight of 10 pounds within about the range 0.50-0.80 gm. per cc.

5. An explosive composition having a density such as toenable the production of in excess of four hundred and twenty-five 1%"x8" cartridges per 100 pounds including as ingredients carbonaceous material, sodium nitrate, and in mechanical admixture therewith crystallized am monium nitrate having a density, determined by dividing the weight in grams of a sample of ammonium nitrate having a volume normally of one cubic inch by the volume of said sample in a closed cylinder one square inch in cross-section under a dead weight of 10 pounds within about the range 0.50-0180 gm. per cc.

6. An explosive composition having a density such as to enable the production of in excess of four hundred and twenty-five 1%"x8" cartridges per 100 pounds including as ingredients carbonaceous material, an oxidizing salt, a sensitizer, and in mechanical admixture therewith crystallized ammonium nitrate having a gravimetric density, determined by dividing the weight in grams of a sample of ammonium nitrate having a volume normally of one cubic inch by the volume of said sample in a closed cylinder one square inch in cross-section under a dead weight of 10 pounds within about the range 0.50-0.80 gm. per cc.

7. An explosive composition having a density 

